Update writingmodules.rst
Update writingmodules.rst

Fixed an error in the module documentation preventing an example from compiling.
neatsun/yara,VirusTotal/yara,jpypi/yara,wxsBSD/yara,pombredanne/yara,neatsun/yara,plusvic/yara,smaudet/yara,plusvic/yara,smaudet/yara,pombredanne/yara,wxsBSD/yara,mgoffin/yara,rayyang2000/yara,frbapolkosnik/yara,hillu/yara,pombredanne/yara,beikezcs/yara,jpypi/yara,cblichmann/yara,tdr130/yara,frbapolkosnik/yara,jshufelt/yara,tdr130/yara,rednaga/yara,Security513/yara,frbapolkosnik/yara,plusvic/yara,plusvic/yara,wxsBSD/yara,hillu/yara,rayyang2000/yara,VirusTotal/yara,frbapolkosnik/yara,msuvajac/yara,Security513/yara,neatsun/yara,msuvajac/yara,hillu/yara,smaudet/yara,beikezcs/yara,msuvajac/yara,rednaga/yara,VirusTotal/yara,rayyang2000/yara,jshufelt/yara,tanium/yara,foreni-packages/yara,wxsBSD/yara,VirusTotal/yara,MeteorAdminz/yara,smaudet/yara,bmagistro/yara,jpypi/yara,foreni-packages/yara,kallanreed/yara,bmagistro/yara,plusvic/yara,jshufelt/yara,jshufelt/yara,cblichmann/yara,foreni-packages/yara,VirusTotal/yara,tdr130/yara,mgoffin/yara,tanium/yara,wxsBSD/yara,kallanreed/yara,tanium/yara,hillu/yara,Security513/yara,MeteorAdminz/yara,MeteorAdminz/yara,mgoffin/yara,pombredanne/yara,bmagistro/yara,cblichmann/yara,kallanreed/yara,rednaga/yara,cblichmann/yara,hillu/yara,mgoffin/yara,cblichmann/yara,beikezcs/yara,pombredanne/yara